Automatic door closing device



June 18, 1968 J. R. SMITH AUTOMATIC DOOR CLOSING DEVICE Filed June '7, 1967 2 Sheets-She et l INVENTOR.

James R. S

June 18, 1968 J. R. SMITH AUTOMATIC DOOR CLOSING DEVICE 2 Sheets-Sheet 2 Filed June '7, 1967 INV EN TOR. James R. Smith III/l HIHII United States Patent 3388554 AUTOMATIC DOOR CLOSING DEVICE James R. Smith, Kirkwood, Ill., assignor to Admiral Corporation, Chicago, Iii, a corporation of Delaware Fiied Home 7, 1967, Ser. No. 644,133 8 Claims. (Cl. 312-319) ABSTRACT OF THE DISCLOSURE Apparatus including a cam surface and biased cam follower for insuring automatic positive closure of a freezer or refrigerator door from a slightly ajar position and providing detenting thereof to prevent accidental opening.

This invention relates in general to freezers and refrigerators, and in particular to the doors required for access to the storage compartments of domestic upright freezers and refrigerators. More particularly, this invention relates to a device for automatically closing freezer and refrigerator doors from a slightly ajar position.

Many conventional domestic upright freezers and refrigerators, especially those of recent manufacture, employ hinges disposed at the top and bottom of the access door as opposed to earlier construction which located the hinges along a side. With the hinges at the top and. bottom of the door, a vertical axis is defined for horiz ontal door movement which allows the door to open without a portion of it overhanging a side of the cabinet. The hinges used to support these doors can be relatively simple and typically comprise upper and lower supporting hinge platese fastened to the cabinet, a depending and an extending hinge pin secured to the upper and lower plates, respectively, and bearings within the door for receiving the hinge pins thereby providing low friction bearing surfaces for effortless door movement.

Typical domestic freezers and refrigerators employ either a rubber or a rubber-magnetic sealing gasket contiguous to the door periphery, facing the cabinet, for sealing the food storage compartment. A good door seal is particularly important in low temperature freezers where there is a substantial temperature differential between the storage compartment and the ambient. The effectiveness of the door seal is a direct function of the operating efficiency of the unit. Further, it is obvious that in order for the sealing gasket to function correctly, it is necessary that the door be fully and securely closed at all times except while removing goods from or placing them in the food storage compartment.

Often during normal use of a freezer or refrigerator, instead of carefully closing the door the user merely swings it shut, hopefully with enough force to fully close the door and establish a tight seal between it and the cabinet. In the event the user misjudges the amount of force necessary to fully close the door, it will remain slightly a-jar. If an interior light is not normally provided in the cabinet, or if the door has been closed sufiiciently to switch the light off, the fact that the door is slightly open can go unnoticed for a long period of time.

Of course, operation of a freezer or refrigerator with the door ajar is extremely uneconomical, especially with frost-free units wherein a circulating fan maintains constant air movement within the storage compartment. In addition, there is the likelihood of an excessive frost buildup on the evaporator or within the cabinet due to a large amount of relatively moist air entering the storage compartment, condensing, and freezing on the cold surfaces. Also, with the door ajar there is the possibility of the food contents defrosting or spoiling as a result of an increase in temperature.

At the opposite extreme, during use of upright freezers and refrigerators the user may slam the door and use excessive force causing the door to contact the cabinet and then bounce or rebound open. Often times the door will remain open just enough to go unnoticed and of course in such a situation, the above-mentioned problems of uneconomical operation and possible spoilage arise.

In some conventional dual compartment combination refrigerator-freezers wherein the compartments are oriented one above the other or side-by-side, and wherein each compartment has a separate door, proper operation requires one or more air ducts connecting the compartments. The ducts provide constant air movement from one compartment to the other. In these units, closing one compartment door too rapidly creates a buildup of air pressure which is communicated through the connecting ducts to the second compartment. Even a small increase in air pressure in the second compartment acting on its large door area could easily force that door ajar.

This invention obviates the above problems and difficulties existing in many freezers, refrigerators, and combination refrigerator-freezers, by providing means housed within the access doors for automatically closing them when they are within a given angular relationship to the cabinet. The automatic closing device is rendered inoperative when an access door is open beyond the given angular position, and requires only a negligible amount of additional force to achieve door movement.

In addition, this invention obviates a vexatious problem existing in two door refrigerator-freezers with regard to accidental door openings caused by closing one door too rapidly, by providing a door detent mechanism integral with the automatic closing mechanism. The detent mechanism requires only a slightly greater effort to open the door from its close-d position, than a door without a detent. The required force is not too great to render the unit unsafe should someone become trapped inside.

Accordingly, it is the primary object of this invention to provide means for automatically closing a freezer or refrigerator door.

Another object of this invention is to provide means for positively closing a freezer or refrigerator door from a given angular position.

A further object of this invention is to provide means for automatically and positively closing a freezer or refrigerator door from a given angular position, wherein said means include integral therewith, a detent preventing accidental opening of said door from an intended closed position.

It is also an object of this invention to provide means for automatically closing a refrigerator or freezer door from a given angular position wherein said means also provide detenting of said door when in its closed position to prevent accidental opening thereof due to rebounding from the cabinet, or due to unequal air pressures in connected adjacent compartments.

Other objects of this invention will become apparent upon an examination of the following description taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a three dimensional view of an upright domestic freezer having a partially cut-away access door showing the location of the invention therein.

FIG. 2 is an enlarged elevation view of the invention taken along line 22 of FIG. 1, with the freezer door in its closed position.

FIG. 3 is an enlarged elevation view of the invention taken along line 3-3 of FIG. 1 showing the location of the operative members when viewed from the back side of the compartment door.

FIG. 4 is an enlarged top plan view of the operative members of the invention showing their relative locations when the door is in its open position.

FIG. 5 is a view similar to FIG. 4 with the door slightly ajar and with the automatic closing device beginning to operate.

FIG. 6 is also similar to FIG. 4 but with the door fully closed, illustrating the operative members in their detent position.

Turning to consideration of the drawings and in particular to FIG. 1, there is shown, for convenience of description, an upright domestic freezer although the invention may also be used with refrigerators and combination refrigerator-freezers. The upright freezer of FIG. 1 includes a cabinet 10, comprising side walls 12 and 14, a top and a bottom 16 and 18 respectively, and an access door 20 having a top surface 19. The access door includes a gasket 21 around its inner periphery (see FIG. 4) and is pivotably hung from the cabinet by an upper hinge generally referred to by reference numeral 22 and a lower hinge 24, not shown. Hinges 22 and 24 are fixed to the top and bottom walls of the cabinet respectively and provide for horizontal pivotal movement of the door about a vertical axis. As shown in the cut-away area, at the upper left-hand corner of the access door an automatic door closing mechanism, which-also includes a door detent, is incorporated in the upper door hinge.

Referring now to FIGS. 2 and 3 the structure of the upper hinge and of the door closer may be seen in greater detail. The hinge structure generally comprises a hinge plate 26 secured to the cabinet top and having a portion overhanging the cabinet front edge, directly above the door. A depending hinge pin 28 is inserted through an aperture 30 provided in the overhanging portion, and into door 20, through an opening 31 provided in its top surface 19. The hinge pin is securely staked to the hinge plate and passes through a nylon spacer 32 before entering opening 31. A door bushing 34 is provided through top surface 19 to insure an adequate bearing area. The lower end of the hinge pin terminates in the interior of the door.

The lower end of the hinge pin is coaxially received by a generally cylindrical cam member 36, preferably fabricated of nylon, to which it is permanently secured by any conventional means. The shape of the cam surface defined by cam member 36 can best be seen in one of the enlarged plan views, such as FIG. 4. It includes a major, generally circular portion 46 and a groove or depression 48. The groove is recessed inwardly from the surface of the circular portion, and includes a substantially radial side wall 49. The cam member also includes integral therewith, a bearing sleeve 44 at the lower end and a door limit projection 50 which extends radially outwardly from the top of the cylinder.

A support bracket 38 is positioned adjacent the cam member and is securely attached to the door interior by fasteners 40. The bracket, which may be fabricated from a metal blank, comprises a horizontally extending double thickness portion 42 having a bearing aperture 45 receiving bearing sleeve 44. The bracket and aperture provide lateral restraint for the hinge pin 28 and the entire upper hinge assembly.

From the description thus far, it can be seen that the hinge plate, hinge pin, and cam member 36 are always stationary relative to the freezer cabinet, and that the door and its bracket 38 pivot relative to the above mentioned members as the door is either opened or closed.

Bracket 38 includes a U shaped portion at its upper end which carries a bell-crank member 52 pivotably secured by a vertical pin 54 staked within the bracket. The bell-crank, which can best be seen in the enlarged plan view of FIG. 4, generally comprises a first arm 56 having a smoothly rounded end or nose 57 which serves as a cam follower. A second bell-crank arm 60, which is the lever arm, forms substantially a right angle with the first arm. A tension spring 58, fixed to a. spring support 58a,

is secured through an aperture 59 in the lever arm and provides the force to pivot the bell-crank counterclockwise about its axis, thereby biasing cam follower 57 into continual contact with the cam surface of cam member 36.

By way of further explanation it can be seen that the bell-crank, its pivot, and the bracket, each move relative to the cam member which is always stationary, while the bell-crank pivots about its axis as the door is opened or closed. Further, tension spring 58 maintains the cam follower in firm contact with the cam surface whether the door is open or closed, although the spring is in a tenser state while the door is open, than when it is closed.

Referring specifically to FIGS. 4, 5, and 6, operation of the automatic door closing mechanism as the door is moved from an open to a closed position, will be detailed. FIG. 4, which illustrates the door in an open position, shows the cam follower biased against the circular portion of the cam. The spring is tensed and exerts a given force P which acts through a distance D of the lever arm providing a given maximum mechanical advantage for the bell-crank.

With the door in its open position, the cam follower follows circular cam surface 46 and exerts a force thereagainst which is directed substantially through the center of the hinge pin. Of course, as is well-known from basic applied mechanics, an equal and opposite force is directed from the cam member to the cam follower, but the direction of this force is also through the center of the hinge pin, thus no moment or torque is produced and movement of the door is unaffected.

FIG. 5 shows the door as it is being closed, in a position of approximately 15 ajar. The door and bell-crank have pivoted about the cam member, and the bell-crank has pivoted about its axis relative to the door. Cam follower 57 is in position to contact the radial side wall 49 of groove 48, and spring 57 is almost fully tensed. With the door in this position, the spring exerts a force F on the lever arm and acts through a distance D. The force and the distance it acts through are slightly less than the respective values when the door is fully open. At this door position, the cam follower imparts a primarily radial force on side wall 49 and an equal and opposite radial force is exerted from the cam member to the follower. This latter force does not pass through the hinge pin, but is in a direction primarily tangential to the circular cam surface, thereby establishing clockwise a torque about the cam member as shown in FIG. 5. This torque is sufiicient to automatically close the freezer door.

In FIG. 6 the door is in its fully closed position and the bell-crank has pivoted clockwise about its axis thereby relaxing Spring 58. The spring force, now represented by F" acts through a distance D", where F" and D" are considerably smaller than the similar values in FIGS. 4 and 5. With the door in its fully closed position, the cam follower is urged into groove 48 and provides a detent for the door thereby preventing it from bouncing open due to an excessive closing force. In two compartment refrigerator-freezers, the detent prevents the door from opening due to an increase of internal air pressure. While the detent also increases the effort which must be applied to the door in order to open it because of the spring condition and the distance through which it is acting, the additional effort is negligible.

Returning now to FIGS. 2 and 4, bracket 38 is provided with an upstanding tab 62 which, of course, is stationary relative to the door. This bracket cooperates with stop 50 of the cam member to define the open limit of the door which, as can be seen from FIG. 4, is about What has been described is an automatic closing device for a door which utilizes a fixed cam member having a circular cam surface adjacent a groove, wherein the groove includes a radial side wall. A bell-crank having a cam follower is biased into continual contact with the cam surface. The follower is ineffective in influencing movement of the door while contacting the circular cam surface but produces a closing torque thereon when following the groove and its radial side wall. When the door is fully closed the cam follower is seated within the groove providing a detent which eliminates undersirable opening due to rebounding or abnormal air pressure.

It is obvious that upon study by those skilled in the art, the disclosed invention may be altered or modified both in physical appearance and construction without departing from its inventive concept. Therefore, the scope of protection to be given this invention should not be limited by the embodiments described above, but should be determined by the essential descriptions thereof which appear in the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a cabinet having a door and a hinge wherein said hinge includes a hinge pin stationary relative to said cabinet, apparatus for effecting positive closure of said door from a given angular position, comprising: means fixed to said hinge pin defining a cam surface having a generally circular major portion concentric with said pin, and a depression parallel thereto; a bell-crank pivotably mounted on said door, having an integral cam follower; spring means cooperating with said bell-crank for biasing said cam follower into continuous firm contact with said cam surface; said cam follower following said generally circular portion and imparting a primarily radial force thereon when said door is open beyond said given angular position, and following said depression when said door is open within said given angular position thereby establishing a force on said cam surface primarily tangential to said circular portion, the reaction of said latter force producing a resultant closing torque on said follower to insure positive closure of said door.

2. The aparatus as set forth in claim 1 wherein said depression comprises a groove having a substantially radial side wall upon which said radial force is established, and wherein said cam follower includes a nose having a round contacting surface co-operating with said radial side wall when said door is open within said given angular position, and seating in said groove when said door is fully closed.

3. The apparatus as set forth in claim 2 wherein said bell-crank includes a lever arm; said lever arm providing a variable mechanical advantage as it pivots for biasing said cam follower into firmer contact with said cam surface when said door is open than when it is closed thereby establishing adequate torque for positively closing said door while allowing it to be easily opened from a normally closed position.

4. The apparatus as set forth in claim 3 wherein said means fixed to said hinge pin includes a radial projection integral therewith interfering with said door for defining a maximum open position.

5. In combination with a refrigerator cabinet having a hinge movably supporting an access door, wherein said hinge includes a vertically disposed hinge pin secured to said cabinet and extending into said door; means housed within said door for effecting automatic positive closure thereof from a given angular position, comprising: a generally cylindrical cam member secured coaxially to said hinge pin; said cam member including a recessed area extending parallel to said hinge pin; a pivotably mounted bell-crank having a cam follower firmly biased into continuous contact with said cam member; said cam follower following the cylindrical portion of said cam member when said door is open beyond said given angular position, and establishing a primarily radial force passing through said hinge pin, and following said recessed area when said door is open within said given angular position thereby establishing a force primarily tangential to said cylindrical cam member, said tangential force resulting in a closing torque on said door.

6. The combination as set forth in claim 5 wherein said bell-crank is of substantially right angle configuration; said cam follower comprising the terminus of a first leg of said bell-crank and a lever arm comprising said second leg; a spring connected to said lever arm for biasing said cam follower; said lever arm providing a variable mechanical advantage and said spring biasing said cam follower with greater force when said cam follower initially follows said recessed area, thereby imposing a relatively large closing torque on said door.

7. The combination as set forth in claim 6 including additionally: a bracket secured to said door defining an aperture in line with said hinge pin; said cam member including an integral bearing portion received by said bracket aperture for lateral support of said hinge pin; and wherein said cam follower is detented in said recess when said door is fully closed, preventing undesirable rebounding thereof away from said cabinet; said spring and the mechanical advantage afforded by said bell-crank allowing said door to be easily opened from a normally closed position.

8. The combination as set forth in claim 7 wherein a tension spring having a relatively low spring constant is used for biasing said cam follower into contact with said cam member.

References Cited UNITED STATES PATENTS 2,392,689 1/1946 Deglow l680 2,614,021 10/1952 Giffard 312-319 2,799,550 7/1957 Rataiczak 16-65 3,344,462 10/1967 W'ebster 1680 JAMES T. MCCALL, Primary Examiner. 

